Pavement-heater flue



G. A. COATS July 8, 1930.

PAVEMENT HEATER FLUE Filed Sept. 8. 192a 2 Sheets-Sheet 1 INVENTOR:eflazafis,

July 8, IQQQ. s. A. COATS 1,770,024

PAVEMENT HEATER FLUE =Fi1ed Sept. 8. 1926 2 Sheets-Sheet 2 ATTORNEYPatented July 8, 1930 UNITED STATES ,PATENT/ OFFICE GEORGE A. GOATS,- OFPHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO GOOD ROADS EQUIPMENTCORPORATION, OF PHILADELPHIA; PENNSYLVANIA, A CORPORATION OF DELAWAREApplication filed September This invention, stated in its broadestterms, relates to a pavement heater as mounted upon a tractor and hasmore especial relation to a flue supported in horizontal position upon asuitable frame carried by the tractor in order that fuel conveyedthrough an inner flue to the pavement heater proper is exteriorly cooledby a current of air travelling first in a direction opposite to thetravel of the products of combustion and thereafter is commingled withthe products of combustion. I

The leading object of the present inven tion may be saidto reside in theprovision of a pavement heater of the character above stated in whichthe flue is comprised of an inner and outer flue partof which the innerflue is of sectional make-up and of refractory material.

A further object is to provide a flue of this character in which coolingair is forced around the inner flue first in a direction opposite to thetravel of the products of combustion and which is then deflected intosaid inner flue where it mixes with the burning ases therein to improvecombustion.

A still further object of the present invention is to provide an innerlining for an inner flue of the character stated in which the liningparts'are 0f sectional character and have nested'relation one with theother.

. A still further object of the present invention is to provide a flueof the character stated in which concentric flues are provided of whichthe inner flue is of refractory ma-- terial and is supported a cradlecarried within the outer flue.

, A still further object of the present invention is to provide astructure of the character stated in which an inner and an outer flueare provided, one end of said outer flue being closed and provided witha fuel supply and the other end connected with a pavement heater and inwhich intermediate the above connections is provided a source of coolingair arranged for passage to the outerflue at the approximately point oftermination of the inner flue. g

A still further object of the present invention is to provide astructure of the charac- PAVEMENT-HEATER rum 8, 1926. Serial No.134,156.

ter stated in. which the said inner and outer fines are of rectangularcross-section and of which the inner flue is of sectional make-up and intwo thicknesses, of which the innermost thickness is carborundum tilesand of which the outer thickness is fire brick tiles. I Other andfurther objects not at this time appearing will be hereinafter moreparticularly referred to.

. The invention consists of the novel construction hereinafter describedand finally claimed.

The nature, characteristic features and scope of the invention will bemore fully on derstood from the following description taken inconnection with the accompanying drawings forming part hereof, and inwhich:

Fig. 1, is a view in side elevation of a pavement heater of the tractortype equipped with a flue embodying the invention.

Fig. 2, is a view in perspective of the frame-work of the tractor forsupporting said flue.

Fig. 3, is a fragmentary view principally in longitudinal sectionshowing the details of construction of the flue.

Fig. 4,- is a view in cross-section taken upon the line 44 of Fig. 3.

Fig. 5, is a view similar to Fig. 3 but illustrating a modified form ofstructure.

Fig. 6, is a view in cross-section taken upon the line 6-6 of Fig. 5.

For the purpose of illustrating my invention I have shown in theaccompanying drawings two forms thereof which are at present preferredby me, since the same have been found in practice to give satisfactoryand reliable results, although it is to be understood that the variousinstrumentalities of which my invention consists can be variouslyarranged and organized and that my invention is not limited to theprecise ar rangement and organization of the instrumentaliti-es asherein shown and described.

Referring to the drawings in detail, and with especial reference to Fig.1, the reference numeral 1 designates a frame as carried by the tractorparts 2 (shown in dotted lines) which frame supports the flue of theinvenof the inner flue to the .5'it is deflected toward the tion. Theflue is horizontally disposed, comprises an outer casing 3 preferably ofsheet metal or the like, the flanged end 4: of whlch has fitted theretoa closure 5 and within which outer casing is located an inner casing 6provided with a lining of refractory material made up of sections 7.Thesesections 7 of refractory material have nested relation as at 8 andare supported within the outer casing 3 by meansof a cradle 9. It may bestated that the inner casing 6 1s in two parts, secured together as at10, as clearly shown in Fig. 1, the casing 6 being preferably of sheetmetal or the like. The sections of refractory material 7 are tubular inform as also clearly shown in Fig. 4. Theouter casing'5 at one end,'orrather the cap 5 of the outer casing 3, is provided with a fuel inletconnection 11 which projects into a funnel shaped mixer 12 where thefuel is burned, the latter being projected well within the inner fluepart, as clearlyshownin Fig. 3. Theopposite end of the outer casing 3has extended therefrom a connection 13 in communication with a hood 14.of conventional form. Intermediate the hood l4 and the fuel con nection11 and connecting with the outer casing 3 isa connection 15 forsupplying cooling air to the outer casing 3 for circulation around theinner casing 6. Asclearly shown in Fig. 3 the cooling air forced by thelower 16 through the connection 15, passes in the direction of thearrows in Fig. 3

around the inner casing 6 within the outer casing 3 in a'directionopposite to that in which the products of combustion pass from theburner 12 through therefractory lining hood 14. Thus, as

the air from the blower 16 circulates around the inner flue it tends tocool the inner flue and prevent undue heating thereof and as it impingesagainst the closed end 17 of the cap left in Fig. 3 and enters the innerflue '6 to improve combustion whence it is forced out through theconnection 13 together with air for supplying the products of combustioninto the hood 14. By having the cap 5 removable and having the innerflue supported upon the cradle 9, it is very easy by removing cap 5 toremove the refractory lining in an endwise direction for replacement orrepair when necessary. In practice the inner and outer casings of theflue are supported by the frame work 1 shown in Fig. 2'in horizontalposition above the working parts of the structure and its variousadjuncts.

The construction shown in Figs. 5 and 6 is substantially that as abovedescribed with the exception that the innerand outer casings are ofrectangular cross-section as is the lining for the inner flue, and inthat the lining for the inner flue is of two thicknesses of which theinner thickness, designated 18, is

' of carborundum tile,andthe other thickness is of fire brick tile andis designated 19. As clearly shown in Fig. 6 these two thicknesses ofrefractory material are of rectangular cross-section and are arrangedwithin an inner flue 20 and the inner flue 20 is spaced from the outercasing 21 by means of brackets 22. Insteadof supporting the inner flueupon a cradle as before described, angle irons 23 are provided upon thebottom of the outer casing 21 upon which angle irons 23 the inner casing20 is supported. While the end of the casing 21, as shown in Fig. 5, isclosed as at 2 1 the part 24: is not in the form of a cap as shown inFig. 3.

What I claim is:

, 1. In a device for pavement heating, an inner, elongated, unobstructedflue forming a combustion chamber and having an intake end and an exitend, means for admitting fluid fuel to the intake end of said flue, asectional lining of refractory material inside of said flue, the liningsections having rabbeted connections, an outer metal casing surroundingsaid flue to form an air passage therearound, and having the end thereofat the intake end of said flue closed, and the opposite end open, andair forcing means connected with the open end of said outer casing nearthe exit end of said flue, adapted to force air through said air passagetoward the closed end of said outer casing to cool said flue, said airbeingthus heated and deflected by the closed end of said outer casinginto the intake end of said flue to com mingle with said fuel to supportcombustion.

2. In a device for pavement heating, an inner, elongated, unobstructedflue, forming a combustion chamber and having an intake end and an exitend, means for admitting fluid fuel to the intake end of said flue, asectional concentric lining of refractory material inside of said flue,the lining sections having rabbeted connections, an outer metal casingsurrounding said flue to form an air passage therearound, and having theend thereof at the intake end of said flue closed and the opposite endopen and extending be yond said flue to form a support for the fueladmitting means, a blower operatively connected with the open end ofsaid outer casmg near the exit end of said flue, and adapted to forceair through said outer air passage toward the closed end of said outercasmg to cool said flue, said air flowing in an opposite direction tothe products of combustion and being thus heated and deflected by theclosed end of said outer easing into the intake end of said flue tocommingle with said fluid fuel, a vertically adjustable hood and aconduit leading from the exit end of sand flue into. said hood forconveyng the products of combuston thereinto.

GEORGE A. COATS.

